For example, a computer device such as a rack mount type server is well known. The computer device includes a front panel rising from a front end of a bottom plate and a rear panel rising from a rear end. In the computer device, a hollow is partitioned from the front panel toward the rear panel on the bottom plate. The printed circuit board is extended along the bottom plate in the hollow. In the hollow, an air flow is produced along a surface of the printed circuit board from the front panel toward the rear panel. Japanese Laid-open Patent Publication Nos. 4-15998, 2003-283171, and 2000-40474 discuss apparatuses wherein the air flow cools electronic parts mounted on the surface of the printed circuit board.